The background of the invention will be set forth in two parts.
1. Field of the Invention
This invention relates to electromagnetic wave generating and amplifying systems, and more particularly to electronic circuitry for transmitting signals from balanced amplifiers or stabilized signal oscillators.
2. Description of the Prior Art
In certain applications, it is desirable to utilize a stable but relatively small injection signal to injection lock (stabilize) two oscillators such as IMPATT diode oscillators, BWO's and klystrons, to provide a very stable and relatively high power output signal. In other applications, it has been found to be desirable to provide an amplified high frequency output signal derived from a pair of matched amplifiers to which is coupled a lower power input signal. For example, it may be desirable to provide a microminiature microwave source of power for use in advanced radar, space and communication systems.
In the past, it has been the long-established practice to use directional couplers or ferrite circulators for injecting the reference signal into and coupling the output signal from a single oscillator. The ferrite circulator scheme requires the use of relatively heavy and bulky magnets, and the directional coupler technique requires a relatively large injection signal. It should therefore be evident that an efficient, convenient, lightweight and compact means for inserting a low level stable reference or input signal to a pair of oscillators or amplifiers, and also for coupling and combining the output energy from these two devices to an output terminal would constitute a significant advancement of the art.